Why Can't A Person Use a Proximity Sensor to Verify a Zero Voltage State for Low Voltage Systems?

This question comes up frequently in electrical safety training classes. This paper will look at how the proximity sensor works. It will examine the limitations of the proximity sensor device that could create a serious safety issue. Then, it will look at the interpretations of Occupational Safety and Health Act on these devices. The regulations do not specify a method nor a device to verify a zero-voltage state that circuits are de-energized, only that it be done. These interpretations are the result of someone getting seriously hurt when using these devices to verify a zero-voltage state.